Page 56 - DJJ 40173 compile notes - E-BOOK NEW EDIT WITH INDEX_Neat

Material classification

Metal Can be further divided into ferrous and nonferrous

alloys, ferrous alloy are based on iron, which has
mechanical properties. Nonferrous alloy are based

on material other than iron such as copper, tin,
aluminium and lead.

Ceramic and glass These are result of the combination of metallic and
non metallic element. they are good insulator,

brittle, thermally stable and more wear resistant
compare with metals. They are also harder and

lower thermal expansion than most metals

Woods and organics These are obtain from trees and plant. Their major

advantages that they are a renewable resource.
However some of their drawback include that they

absorb water, required special treatment to
prevent rotting and are more flammable

Polymers and plastics These material change viscosity with variation in
temperature, easy told into given shape. Good

insulator , resistance to chemical and water,

smooth surface finish, available in many colour
(eliminate painting), low strength, deteriorate in

ultraviolet light.